title: Inhibitory effect of minocycline on osteoclastogenesis in mouse bone marrow cells.
abstract: OBJECTIVE
  To study the effects of minocycline hydrochloride (MINO) on the formation of tartrate-resistant acid phosphatase (TRAP) staining-positive multinucleated osteoclast-like cells in mouse bone marrow cells (BMCs) treated with 1α,25(OH)(2)D(3) or soluble receptor activator of nuclear factor-κB ligand (s-RANKL).
  
  
  METHODS
  Mouse BMCs were cultured in alpha-modified minimum essential medium containing foetal calf serum (10%) and tetracyclines (2.5, 5 and 10μM), such as MINO, tetracycline hydrochloride (TC), oxytetracycline hydrochloride (OXT) or doxycycline (DOXY) in the presence of 1α,25(OH)(2)D(3) (10nM) or s-RANKL (20ng/ml) for 7 days, and the number of TRAP staining-positive osteoclast-like cells was counted. In RNA isolated from BMCs treated with 1α,25(OH)(2)D(3) or s-RANKL in the presence or absence of MINO, the expressions of osteoclast differentiation relating to mRNA were analysed by reverse transcription-polymerase chain reaction. Cell viability was examined in mouse BMCs and rabbit osteoclasts treated with MINO (0.25-20μM and 2-50μM, respectively) for 24h.
  
  
  RESULTS
  MINO, TC, OXT or DOXY inhibited 1α,25(OH)(2)D(3)-induced osteoclast-like cell formation in mouse BMCs dose dependently. MINO suppressed 1α,25(OH)(2)D(3)-induced up-regulation of mRNA expressions of TRAP, cathepsin K, carbonic anhydrase II, and calcitonin receptor, but not RANKL. MINO inhibited s-RANKL-induced osteoclast-like cell formation and up-regulation of mRNA expressions for nuclear factor of activated T-cells c1 (NFATc1), a key regulator of osteoclast differentiation; however, MINO had no effects on the viability of mouse BMCs and rabbit osteoclasts.
  
  
  CONCLUSIONS
  MINO inhibits RANKL-induced osteoclastogenesis via down-regulation of NFATc1 mRNA expression in osteoclast precursor cells.
authors.affiliation: Department of Pharmacology, School of Dentistry, Aichi-Gakuin University, 1-100 Kusumoto-cho, Chikusa-ku, Nagoya 464-8650, Japan.
authors.forename: Tsuneyasu
authors.initials: T
authors.lastname: Nagasawa
authors.forename: Michitsugu
authors.initials: M
authors.lastname: Arai
authors.forename: Akifumi
authors.initials: A
authors.lastname: Togari
mesh_terms: D000135:Acid Phosphatase / Q000378:metabolism; D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001854:Bone Marrow Cells / Q000166:cytology / Q000187:drug effects*; D002117:Calcitriol / Q000494:pharmacology; D002454:Cell Differentiation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D015536:Down-Regulation; D007527:Isoenzymes / Q000378:metabolism; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D008911:Minocycline / Q000494:pharmacology*; D050778:NFATC Transcription Factors / Q000096:biosynthesis*; D010010:Osteoclasts / Q000166:cytology / Q000187:drug effects*; D053245:RANK Ligand / Q000494:pharmacology; D011817:Rabbits; D000071681:Tartrate-Resistant Acid Phosphatase
chemical_list: D000900:Anti-Bacterial Agents; D007527:Isoenzymes; D050778:NFATC Transcription Factors; D053245:RANK Ligand; D000135:Acid Phosphatase; C000605511:Acp5 protein, mouse; D000071681:Tartrate-Resistant Acid Phosphatase; D002117:Calcitriol; D008911:Minocycline